Transcript
Unit 6
T-test for independent samples
The t-test is a test difference between two independent groups. The means are compared Mean 1 against the Mean 2.
When do we use the t-test for independent samples?
When we compare the means of two independent groups.
When the data are expressed in interval and ratio.
When the sample is less than 30.
F-Test
The F-test (ANOVA- Analysis of Variance) is another parametric test used to compare the meansof three or more groups of independent samples.
Why do we use F-test? Because we want to find out if there is a significant difference between and among the means of three or more independent groups.
A B C
8 14 10
7 16 12
9 12 16
13 17 15
10 11 12
Exercise
In an experiment to determine the germicidal effect of 3 brands of bath soap, 5 groups of nursing students were randomly assigned to each of the 3 popular brands of soap: Brand A, B, and C. Bacterial count after 1 hour of using the soap was recorded as shown in table1. Find if there’s a significant difference (5% level) among the different brands of soap using ANOVA.
BRAND
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